Low abundance noncoding antisense RNAs are transcribed from the opposite strand of many genomic loci. These endogenous regulatory elements are shown to regulate corresponding mRNA expression, in some cases through the recruitment of epigenetic enzymes that induce locus-specific chromatin modifications. Inhibition or removal of this subset of antisense transcripts leads to locus-specific up-regulation of sense mRNA and functional protein. We found that brain-derived neurotrophic factor (BDNF) is under the regulatory control of antisense RNAs that transcriptionally suppress the expression of sense mRNA and protein. The main goal of this proposal is to study the role of noncoding RNAs as epigenetic modulators of BDNF expression. Initially, we will study the mechanism of antisense RNA-mediated regulation of BDNF, in vitro, in primary cultures of human and mouse neuroepithelial cells. We will then develop tools to quantitatively measure the interaction between BDNF antisense RNA (BDNF- AS) and the epigenetic enzyme EZH2 to investigate the structural and/or sequence requirements of this interaction. Lastly, we will examine the in vivo effects of Bdnf-AS knockdown on the Bdnf locus, utilizing a mouse model of Rett syndrome (Mecp2 null mice). Studies planned under this proposal will shed light on the molecular mechanisms by which noncoding antisense RNAs, in particular BDNF-AS, regulate expression at the BDNF locus. Our unique approach will lead to identification of the molecular underpinning of noncoding RNA- protein interactions. Finally, we will study the in vivo regulatory role of endogenous BDNF-AS in a mouse model of Rett syndrome. Overall these projects will pave the road for future epigenetic studies on other genomic loci, serving to establish novel noncoding RNA therapeutic targets for several neuropsychological disorders.